In this invention, the polymerization catalysts useful in polymerizing and interpolymerizing 1-olefins are prepared by the reaction of silica or alumina with a functional phosphorus compound, organomagnesium compound, a titanium, vanadium, zirconium, chromium or mixture of these compounds, and a magnesium compound. These catalysts are then activated by associating them with an organoaluminum cocatalyst. These catalyst products are primarily useful for the polymerization of 1-olefins such as ethylene and the interpolymerization of these 1-olefins.
One of the features of this invention is to provide polymerization catalysts by reacting silica, alumina, or a mixture with a mono- or a multifunctional phosphorus compound, a titanium compound, and an organomagnesium compound. These catalysts are then activated by an organoaluminum compound. These catalysts are useful in the polymerization of .alpha.-olefins and in the interpolymerization of ethylene with other .alpha.-olefin monomers.
Another feature of this invention is to provide a catalyst with controlled comonomer incorporation so that ethylene may be interpolymerized with .alpha.-olefins, leading to the production of improved polyolefin resins. The control is achieved by utilizing different mono- or multifunctional phosphorus compounds and their relative amounts.
K. Ziegler first discovered that the combination of compounds from Groups IV-VIB metals of the periodic table and an organometallic compound belonging to Groups I-IIIA of the periodic table formed catalysts suitable for polymerizing .alpha.-olefins. In subsequent years, several catalysts have been disclosed as improvements over the original Ziegler catalysts. Unfortunately, many of these catalyst systems exhibit relatively low activity, low stability, and often require a costly and time-consuming catalyst removal step.
Attempts to modify Ziegler catalysts by depositing the catalyst components on an inert support have been made. Such a process is disclosed in U.S. Pat. No. 2,981,725. The supports disclosed were MgCl.sub.2, silicon carbide, silica gel, CaCl.sub.2, etc. These catalysts still exhibit low activities.
U.S. Pat. Nos. 3,654,249; 4,097,409; 4,082,692; 4,039,472; and 3,759,884 describe several catalysts in which titanium and vanadium halides are deposited on a support. These supports include magnesium alkoxides, magnesium chloride, magnesium hydroxy-halides, and the like.
In U.S. Pat. No. 4,243,552, a phosphorus modified support is disclosed. In this case, MgCl.sub.2 is ball milled with an organophosphorus compound to form a support. This catalyst component is then combined with excess TiCl.sub.4. Extensive washings are required to obtain the final catalyst. This system has the severe drawback of the environmental impact of the TiCl.sub.4 containing "effluents".
British Pat. No. 2,049,709A discloses a catalyst system in which the modified silica support is prepared by reacting the silica with "chlorinating" agents. The list of chlorinating agents used includes PCl.sub.5, PCl.sub.3, POCl.sub.3, as well as nonphosphorus-containing chlorine compounds. This patent does not disclose the use of any organophosphorus compounds.
None of the above prior art patents disclose that the treatment of an inorganic material such as silica or alumina (1) after treatment with a reactive mono- or multifunctional phosphorus compound, (2) then an organometallic compound of Group IIA or a complex and subsequently (3) with a Group IVB or VB halide or alkoxide gives a superior catalyst suitable for .alpha.-olefin polymerization in the particle form, gas-phase, or solution form processes. Steps (2) and (3) above may be reversed.